March 3rd 2017:
Wild African elephants sleep for the shortest time of any mammal, according to a study. Scientists tracked two elephants in Botswana to find out more about the animals’ natural sleep patterns. Elephants in zoos sleep for four to six hours a day, but in their natural surroundings the elephants rested for only two hours, mainly at night.
The elephants, both matriarchs of the herd, sometimes stayed awake for several days. During this time, they travelled long distances, perhaps to escape lions or poachers. They only went into rapid eye movement (REM, or dreaming sleep, at least in humans) every three or four days, when they slept lying down rather than on their feet.